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How to unblock ports and enable services in the firewall

 
 
HPLIP Version: 
All
Printer(s): 
All
Linux OS Distribution(s): 
opensuse, rhel
Notes: 
 

1 Firewall Settings

HPLIP uses service discovery protocols like avahi, SLP to discover network resources like printers in a Local Area Network(LAN). These services listen at well defined port numbers. Therefore to allow resource discovery, it is required certain ports should not be blocked by firewall, if any, running on the host machine. By default in OpenSuse/RHEL etc., all the ports are blocked due to security considerations. In this particular scenario HPLIP cannot discover the printers on LAN using network discovery methods (slp, avahi, mDNS/bonjour). To allow network discovery methods to discover printers in LAN follow the steps mentioned below.

OpenSUSE

Avahi

  1. Go to Yast Control Center and click on Firewall.
  2. Select Allowed Services on the left hand side pane.
  3. Click on Service to Allow drop-down, which will show a list of services we can enable using this firewall utility.
  4. To allow avahi to discover the devices through hp-setup utility, select Zeroconf/Bonjour Multicast DNS and select Add from drop down, and click on Next at the bottom right corner.
  5. The OpenSuse Firewall Utility will display Firewall Configuration Summary. Click on Finish to compelete the process.

mDNS/Bonjour

  1. Go to Yast Control Center and click on Firewall
  2. Select Custom Rules on left pane, select Zone as External and then select Add at the bottom. A pop up will appear .  Provide the values of the parameter as : Source Network  0/0, Protocol UDP, Ports 5353
  3. Click on Add at the bottom right.
  4. The OpenSuSe rewall utility will display Firewall Conguration Summary Click on Finish to complete the process.

SLP

  1. Go to Yast Control Center and click on Firewall.
  2. Select Custom Rules on left pane, select Zone as External and then select Add at the bottom. A pop up will appear .  Provide the values of the parameter as : Source Network  0/0, Protocol UDP, Ports 427
  3. Click on Add at the bottom right.
  4. The OpenSuSe rewall utility will display Firewall Conguration Summary Click on Finish to complete the process.

For advanced usage of the SuSeFirewall2 utility and more details about the above options check the following link https://en.opensuse.org/SuSEfirewall2
 

RHEL

mDNS/Bonjour 

1.Go to Firewall Configuration on RHEL system.
2. Switch to Public->Ports tab.
3. Click Add button.
4. Input 5353 in Port/Range text box.
5. Select protocol type as udp.
6. Save the changes.